Revision as of 19:32, 13 May 2013

Calc Add-ins

Function to return roots of quadratic equation

Formerly bug 122171

Quadratic equation ax^2+bx+c=0

Proposed added function:

• quadratic(a,b,c,1) will return (-b+sqrt(b^2-4ac))/(2a)
• quadratic(a,b,c,2) will return (-b-sqrt(b^2-4ac))/(2a)
• error if complex root

Numerical integration - Simpson's rules

Formerly bug 122202

Given: equally spaced x values, x0 till xn and respective function values in two columns

• Three points n=2: Simpson's 1/3 ruleFunction

 Simp13 = (x2-x0)*(f(x0)+4f(x1)+f(x2))/6

• Four points n=3: Simpson's 3/8 ruleFunction

 Simp38 = (x3-x0)*(f(x0)+3f(x1)+3f(x2)+f(x3))/8

• Five points n=4: Simpson's 1/3 rule on first and last three points

• Six points n=5: Simpson's 1/3 rule on first three points and Simpson's 3/8 rule on last last four points

• etc.

Function to return astrological sign

Proposed added function:

• astrosign(19/07/2013)=Cancer

Function to return calling code

Proposed added function:

• callcode(Colombia)=57

Function to return chemical compound formula

Proposed added function:

• chemform(water)=H2O

Resistor color code calculator

Proposed added function:

• rescol(brown,red,orange)=12000 (ohm)

Newton Raphson solver

Proposed added function: given f(x)=0, d/dx(f(x))

• newraph(x,f(x),d/dx(f(x)),eps)=x-f(x)/(d/dx(f(x))

eps=convergence criteria

secant solver

Proposed added function: given f(x)=0 (unlike Newton Raphson, function derivative not given)

• secant(x_i-1,x_i,f(x),eps)=x_i-(f(x_i)*(x_i-1-x_i))/(f(x_i-1)-f(x_i))

eps=convergence criteria